aBeginning in 2008, data are no longer collected and are assumed to be zero.

hIncurred in the generation, transmission, and distribution of electricity plus plant use and unaccounted forelectrical system energy losses. Pre-1990 estimates are not comparable to those for later years. See Section6 of Technical Notes for an explanation of changes in methodology.

bNatural gas as it is consumed; includes supplemental gaseous fuels that are commingled with naturalgas.

– – = Not applicable. NA = Not available.

cLiquefied petroleum gases, includes ethane and olefins.

Where shown, R = Revised data and (s) = Physical unit value less than 0.5 or Btu value less than 0.05.

dWood and wood-derived fuels.

Notes: Totals may not equal sum of components due to independent rounding. · The continuity of thesedata series estimates may be affected by changing data sources and estimation methodologies. See theTechnical Notes for each type of energy.

eThere is a discontinuity in this time series between 1988 and 1989 due to the expanded coverage ofrenewable energy sources beginning in 1989.

Sources: Data sources, estimation procedures, and assumptions are described in the Technical Notes.

gBeginning in 1980, adjusted for the double-counting of supplemental gaseous fuels, which are included inboth natural gas and the other fossil fuels from which they are mostly derived, but should be counted only oncein net energy and total.